CDI is a bacterial infection of the gut that often causes diarrhea in hospitalized patients, is becoming increasingly common (with the number of cases doubling over the last decade), and costs the nation up to $1 billion in healthcare expenditures.

By analyzing three groups of patients with CDI — those who were admitted from the community with no risk factors, those who had prior exposure to hospitals or clinics, and those who had onset of disease in the hospital — the researchers found people infected outside a hospital setting were far more likely to be obese than the others.

"We were also surprised to note that our patients who were presenting from the community were almost twice as likely to be obese as the general population in Massachusetts [34 percent compared to 23 percent]," said Nahid Bhadelia, M.D., associate hospital epidemiologist at BMC and assistant professor of medicine at BUSM.